Inventories Stated at Lower of Average Cost or Market (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Mar. 31, 2013
Inventory Disclosure [Line Items]
Inventories	$ 162,094	$ 156,380
Raw Materials and Material-in-Progress [Member]
Inventory Disclosure [Line Items]
Inventories	71,298	56,019
Finished Cement [Member]
Inventory Disclosure [Line Items]
Inventories	12,327	18,077
Gypsum Wallboard [Member]
Inventory Disclosure [Line Items]
Inventories	6,112	6,855
Aggregates [Member]
Inventory Disclosure [Line Items]
Inventories	12,421	16,837
Paperboard [Member]
Inventory Disclosure [Line Items]
Inventories	3,412	2,867
Repair Parts and Supplies [Member]
Inventory Disclosure [Line Items]
Inventories	51,011	49,361
Fuel and Coal [Member]
Inventory Disclosure [Line Items]
Inventories	$ 5,513	$ 6,364